The present invention relates to an endoscope for use in medical and other fields and more particularly to an endoscope that has achieved a brake for keeping bent a bending portion located at the distal end of an insertion section without resorting to a mechanical configuration using, for example, friction.
As is well known, an endoscope includes an insertion section that is inserted into the human body, a manipulating section for manipulating the insertion section and performing other operations of the endoscope such as air supply/water supply, a connector (LG (light guide) connector) connected to an air supply source, a suction pump, etc., and a universal cord (supply hose) for connecting the connector to the manipulating section and the insertion section.
As disclosed in, for example, JP 11-47082 A, JP 2000-229061 A, and JP 2001-346756 A, an endoscope typically comprises a bending portion close to the distal end of the insertion section such that the bending portion can be bent up and down, and left and right, by turning manipulative knobs provided on the manipulating section.
Generally, bending of the bending portion is achieved by drawing it with a wire.
Specifically, the bending portion comprises numerous rings arrayed and linked in a tubular-form and wires inserted through these linked rings. The rings are linked so that they may pivot (swing) up and down, and left and right, alternately in two orthogonal directions. A total of four wires, two wires spaced apart up down and two wires spaced apart left and right, are inserted through the linked rings; the distal ends of such wires are secured to a ring positioned closest to the distal end.
The manipulative knobs include a UD (up/down) knob for bending the bending portion up and down and an LR (left/right) knob for bending the bending portion left and right.
The two wires inserted through the rings of the bending portion and spaced apart up and down are passed over a pulley that turns integrally with the UD knob. Likewise, the two wires spaced apart left and right are passed over a pulley that turns integrally with the LR knob.
Therefore, by turning either of the manipulative knobs, one of the paired wires linked to the bending portion is withdrawn while the other wire of the pair is advanced to bend the bending portion. The bending portion can be bent to any of the directions including the up and down direction and the left and right direction by manipulating both the UD knob and the LR knob.
The examinations and treatments using an endoscope vary in kind; there are cases where the endoscope needs to be operated with the bending portion kept greatly bent.
For instance, as conceptually illustrated in FIG. 7, the gastric fundus is examined by turning the insertion section in the stomach about the axis along which it extends, with the bending portion kept greatly bent.
Thus, in such an examination, a doctor who manipulates the endoscope needs to turn the insertion section while holding a manipulative knob or knobs to keep it from turning backwards by resisting a great counter force while holding the heavy manipulating section. Thus, the doctor must bear an extremely great burden. If the doctor carelessly releases his/her hold on a manipulative knob, the bending portion will return to its straight shape at a stroke due to a strong counter force, which may damage the human body.
As a counter thereto, a typical endoscope is equipped with a so-called brake for keeping the bending portion bent as described also in JP 11-47082 A, JP 2000-229061 A, and JP 2001-346756 A cited above.
A typical brake keeps the manipulative knobs from turning through, e.g., friction, or otherwise mechanically holds in position the manipulating means for the bending portion or the bending means for bending the bending portion, with the bending portion kept bent, thereby to hold the bending portion kept bent by a desired bend amount. Therefore, such a brake may be used to eliminate the load that must be borne to hold the manipulative knobs in position against the counter force produced by the bending portion when performing an operation such as turning the insertion section with the bending portion kept bent.